The mechanical properties of photopolymer prepared via 3D stereolithography printing: The effect of UV curing time and anisotropy

Abstract

Stereolithography is a high accuracy additive manufacturing process that uses a laser beam to cure photopolymer resin according to the computer-aided design file. Anisotropy in mechanical properties is one of the major challenges that are faced by additive manufacturing technologies. This study is conducted on PR 48 photopolymer samples using FORM 2 SLA printer. Elastic modulus and hardness of printed samples of 50 and 100 μm resolutions were tested at 0°, 45° and 90° orientations using nanoindentation testing machine. The samples were cured using UV, and the effect of UV curing time was investigated. Results for 100 μm print resolution showed that elastic modulus and hardness for 0° orientation is higher than 45° orientation by 35 % and 390 % for 90° print orientation. For 50 μm print resolution, elastic modulus and hardness for 0° orientation are higher than 45° orientation by 106 % and higher by 92 % for 90° orientation. The results show a strong dependency of mechanical properties on print orientation, resolution and UV curing time and temperature.